Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 23 for “"Electrowinning"”.
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Improving base metal electrowinning
<p>"In zinc electrowinning, Mn oxidizes to form MnO<sub>2</sub> on Pb-Ag anodes, cell walls and pipes. MnO<sub>2</sub> reduces anode corrosion but also leads to short circuits and maintenance issues. MnO<sub>2</sub> is thought to interact with chloride ions and produce oxidized chlorine species. …
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Electrochemical evaluation of anodes in lead electrowinning
… and electrochemically attractive anode in the electrowinning step. A high reaction rate of oxygen evolution and a low generation of lead dioxide are necessary to ensure a satisfactory efficiency. One way to inhibit the formation of lead dioxide is by employing additives, such as phosphorus or …
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Application of a porous diaphragm in a calcium electrowinning cell
Includes bibliographical references (pages 105-109).
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The effect of mass transport on deposit quality in copper electrowinning
… electrode surface. Mass transfer properties in electrowinning electrolytes were first characterized. The effective diffusivity of cupric ion was measured with a rotating disk electrode in CuSO<sub>4</sub>-H<sub>2</sub>SO<sub>4</sub> electrolytes at temperatures relevant to electrowinning, with …
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Investigation of the electrowinning of neodymium oxide in room temperature ionic liquid
… from neodymium oxide at low temperatures. Electrowinning technique for reduction of neodymium oxide in room temperature ionic liquid is designed, discussed and evaluated. The chemical process for synthesis of Nd(TFSI)3 from Nd2O3 and hydrogen-cation-based ionic liquid (HTFSI) is described. …
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Electrowinning of cobalt at high cathodic current densities (400-1000 A M-2)
… 40O Am to 1000 Am were used to investigate the electrowinning of cobalt from sulfate solutiaiie. The cell used was a cylindrical beaker of 1000 ml capacity. Two lead anodes and one stainless steel cathode were used as - electrodes. The cathode was prepared electrolytically with a solution of …
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Review of methods for the elimination of principal impurities from electrolytes used in zinc electrowinning, A
Includes bibliographical references.
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Investigation of solvent-extraction options for zinc recovery from high chloride solutions for the Anglo Research Zinc process
… plate metal and chlorine gas generated from an electrowinning step.
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Solar energy in the minerals processing industry: identifying the first opportunities
… energy. Comminution, hot leaching processes and electrowinning circuits are shown to be the most energy intensive areas. Comminution requires high voltage AC power which can be supplied by the solar thermal (ST) technology which converts solar heat to steam which then drives a turbine. Process …
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Electrochemical speciation and quantitative chromatography for modelling of indium bioleaching solutions
… sulfate, and hydroxide ions, as well as with electrowinning additives. High pressure liquid chromatography techniques were adapted to quantify polysulfides (Sx2–) and metal ions in leaching and extraction solutions. This cumulative information was used in geochemical modelling. Predominance, …
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Ionic liquid electrochemical processing of reactive metals
… Aluminium was electrodeposited using both an electrowinning setup (chlorine evolution anode reaction) and electrorefining setup (Al dissolution anode reaction). The deposits were characterized in terms of morphology, current efficiency and power consumption. A variety of deposit morphologies …
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Electrorefining of base metal refinery residue copper alloy for platinum group metal recovery
… slimes. Spent electrolyte from the BMR copper electrowinning section adjusted to specific pH and Cu concentration is used as electrolyte to which dissolvable metals (such as Ni and Fe) are recovered.
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Method of Measuring Ohmic Resistance in Aluminium Reduction Cells
… were conducted on a 500 A laboratory copper electrowinning cell with geometry similar to that of an industrial aluminium reduction cell. Inductance again had a significant impact on the performance of the measurement technique, but the measurement parameters could again be optimised such that …
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A techno-economic comparison of three process routes for the treatment of Gamsberg zinc ore
… followed by the roast-leach-electrowinning (RLE) process. This route has major detrimental impacts on the environment, it produces SO2, and cannot treat ores of low grade or higher complexity. Therefore, alternative processes are being sought in order to circumvent the RLE …
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Metals recovery from industrial wastewaters and metallic hydroxide sludges through microbial sulphate-reduction.
… selective precipitation, ion exchange, and electrowinning. These processes are capable of recovering metals in a pure form, however, this technology does not appear to be economical at this time due to high energy costs, high chemical cost, and undue competition of this pure product from …
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Electrochemical study of gold thiosulfate extraction process
… species in the electrolyte on gold electrowinning process. It was found that the addition of sulfite to the electrolyte resulted in the formation of Au(S2O3) SO3)25- as the most stable gold complex which decreased the gold reduction rate. However, it restricted thiosulfate …
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Using simulation and lab validation to develop a MnCO3 Recovery Process using CO2
… of HPMSM but conventional purification using electrowinning is energy-intensive, unsustainable, and environmentally harmful. Therefore, this study aimed to investigate the feasibility of chemical precipitation using a greenhouse gas (carbon dioxide gas, CO2) and ammonia (NH3) as a sustainable …
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Investigation into the kinetics, mechanisms and particle characteristics of selenium precipitation from copper sulphate solution.
… from copper sulphate solution prior to the electrowinning of copper is desirable in order to minimise contamination of the copper cathodes by selenium and other impurities. The selenium removal is effected by a precipitation process that takes place under high supersaturation conditions …
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